Huh. Sorry about your ferret, that really sucks. For what it's worth, summons do seem to work here.

[ we're just gonna... gloss over the part about casually raising the undead. that... that's fine ]

You can't estimate based on how much you'd pay for the stuff in gold? Say if you've got an apple, you'd pay 1 gold but it costs 2 demichroma here, that's a 1:2 ratio. Pretty simple math from there.